Recording apparatus for electrographic imaging

ABSTRACT

A recording head comprising a plurality of wires embedded uniformly spaced from each other in parallel relationship in insulating material with at least one end of each wire projecting beyond the insulating material and serving as a writing electrode. Connector means are connected to each of the wires for applying electrical signals thereto. These connecting means are preferably in the form of contact pins, extending normal to the wires, and each connected at one end to the respective wire and projecting with the other end beyond the insulating material.

United States Patent 1 Biiuerlen i 1 RECORDING APPARATUS FORELECTROGRAPHIC IMAGING [75] Inventor: Hans Biiuerlen, Gerlingen, Germany[73] Assignee: Robert Bosch G.m.b.H., Stuttgart,

Germany [22] Filed: Nov. 23, 1973 [21] Appl. No.: 418,773

Related US. Application Data [62] Division of Ser. No. 256,976, May 25,1972, Pat. No.

[30] Foreign Application Priority Data May 26, i971 Germany 2126043 [52]US. Cl. 346/74 ES; 346/139 C [51] Int. Cl. G03G 15/00 [58] Field ofSearch 346/74 E, 74 ES, 74 S,

346/74 SB, 74 SC, 74 CH, 139 A, 139 C [56] References Cited UNITEDSTATES PATENTS 3.317.917 5/1967 Little 346/74 E 1 July 1, 1975 3,363,2611/1968 Maiershofer 346/74 E 3,618,118 11/1971 Lloyd 346/74 ES 3,623,12211/1971 Fotland 346/74 E 3,718,936 2/1973 Rice, Jr........ 346/!39 C3,798,756 3/1974 Bauerlen 346/[39 C Primary Examiner-Daryl W. CookAssistant Examiner-Jay P. Lucas Attorney, Agent, or Firm-Michael S.Striker [57] ABSTRACT A recording head comprising a plurality of wiresembedded uniformly spaced from each other in parallel relationship ininsulating material with at least one end of each wire projecting beyondthe insulating material and serving as a writing electrode. Connectormeans are connected to each of the wires for applying electrical signalsthereto. These connecting means are preferably in the form of contactpins, extending normal to the wires, and each connected at one end tothe respective wire and projecting with the other end beyond theinsulating material.

6 Claims, 2 Drawing Figures RECORDING APPARATUS FOR ELECTROGRAPHICIMAGING CROSS REFERENCE TO RELATED APPLICATIONS The present applicationis a divisional application of the copending application Ser. No.256,976, filed May 25, 1972 now U.S. Pat. No. 3,798,756.

BACKGROUND OF THE INVENTION The present invention relates to recordingheads with a plurality of insulating writing electrodes which are placedadjacent to one another for use in an apparatus to record information ona recording medium.

In connection with high-speed printers or the like, it is necessary toutilize a plurality of writing electrodes which are uniformly spacedadjacent to one another so that characters or letters and numerals canbe recorded on a recording surface. In such apparatus, the letters andnumbers are produced by the formation of a plurality of markings which,when used as a whole make up the letters or numerals. More particularly,the known apparatus records the information by producing a rasterwherein the simultaneous production over the width of the record carrierof dots or short lines, when recorded selectively by the plurality ofrecording electrodes, and while the recording medium is moving, canproduce or generate the outlines of the letters or numerals.

It is already known, in connection with recording heads of this type, toplace a plurality of writing electrodes adjacent to one another and toseparate the same by insulating plates, which act as spacerstherebetween, and then to package the entire assembly to produce arecording head. Such a construction is disclosed in the U.S. Pat. No.1,524,340. However, this type of construction of recording heads is noteconomical and the required tolerances of the insulating spaces add tothe cost, so that not only the construction becomes very expensive, butalso of large width.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a recording head which does not have the disadvantages of suchrecording heads known in the art.

It is a further object of the present invention to provide a recordinghead wherein the plurality of electrode wires can be spaced as close asdesired without running the risk of producing shorts therebetween.

It is a further object of the present invention to provide a recordinghead which is either rigid or flexible so that the recording head may bebuilt in to recording apparatus without interfering with othercomponents of the recording apparatus.

With these and other objects in view, which will be come apparent as thedescription proceeds, the recording head according to the presentinvention mainly comprises a plurality of conductors, embedding meansfor embedding the plurality of conductors in closely spaced parallelrelationship with at least one of the ends of each conductor projectingbeyond the embedding means, and connector means connected to each of theconductors for applying electrical signals thereto.

According to a preferred embodiment of the apparatus, the connectormeans comprise a plurality of electrical contact pins, one for eachconductor, and each connected at one end to the respective conductor,

while projecting with the opposite end beyond the embedding means.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and the method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view of arecording head according to the present invention: and

FIG. 2 is a perspective view of another embodiment ofa recording headaccording to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

Referring now to the drawing, and more specifically to FIG. 1 of thesame, it will be seen that the recording head 22 according to thepresent invention may comprise a substantially plate-shaped member 20 ofplastic insulating material in which a plurality of conductors in theform of blank wires 23 are embedded in closely spaced parallelrelationship so as to be insulated from each other by the plasticinsulating material. In the construction of the recording head 22, asshown in FIG. 1, the opposite ends 23a of the conductors 23 projectbeyond opposite end faces of the plate-shaped block 20 of insulatingmaterial to serve as writing electrodes. The recording head 22 includesfurther a plurality of connector means, one for each of the wires 23,which are shown in FIG. 1 as contact pins 17, each connected at 24 to arespective one of the wires 23 by welding or soldering and projectingfrom the connected end in substantially normal direction to therespective wire through and beyond the body 20 of insulating material tobe connected at its outer end 17b projecting beyond the insulating body20 to a female connector, not shown in the drawing, so that each of thewires may be supplied with electrical signals. As shown in FIG. I, theconnecting points 24 between each of the connector pins I7 and thecorresponding wire 23 are displaced from each other in the longitudinaldirection of the wires so that the outer ends 17b of the contact pinswill be spaced from each other a distance greater than the transversespacing of the wires 23.

With the recording head as illustrated in FIG. I in which the wires 23project with opposite ends 23a, forming writing electrodes, beyondopposite ends of the insulating body 20, the recording head 22 may beutilized on one side or the other, or on both sides simultaneously.Thus, by providing recording material at opposite ends of the insulatingbody 20 and by applying suitable electrical signals to the contact pinsI7, two records may be simultaneously imprinted on two recordingsurfaces in contact with the free ends of the writing electrodes 23a,while the recording surfaces move in a direction substantially normal tothe longitudinal direction of the recording head. On the other hand, therecording head shown in FIG. I may be used with only one recordingsurface in contact with the free ends of the writing electrodes 23aprojecting beyond one end of the recording head, and after theprojecting ends 23a of the wires 23 are worn after extended use of therecording head, the recording head may be reversed so that the unusedprojecting ends 23a may then contact the recording surface.

Fl(]. 2 shows another embodiment of a recording head according to thepresent invention. While the body of the recording head 22 shown in FIG.I is made of substantially rigid, for instance transparent plasticmaterial, in the recording head 34 shown in FIG. 2 the parallel wires 35are embedded between two plastic foils 32 and 33 which are fusedtogether on abutting surfaces thereof and these foils are made fromflexible plastic material so that the resulting recording head is in theform of a flat cable which may be bent around intervening components,such as a bar 36 which may form part of the recording apparatus. Such arecording head is suitable for apparatus for picture transmission aswell as for so-called numerical writers, in which the entire width ofthe recording head is utilized. in the recording head 34 illustrated inFIG. 2, the opposite ends 350 and 35b of the wires 35 which are embeddedin close and parallel relationship between the fused plastic foils 32and 33, likewise project beyond the embed ding material so that forinstance the ends 350 which lie in a straight line, may make contactwith a record carrier 37, travelling in the direction as indicated bythe arrow with respect to the recording head 34 and which may be formedby a metallized web capable of being oxidized or burned by applicationof a voltage thereto by the ends 35a. In this manner, by selectivelyapplying voltages to the ends 35a, while the record carrier 37 ismoving, letters, numerals as well as picture recordings can be made. Theconnections to the wires 35, forming with their projecting ends 35awriting electrodes, can be made either at the ends 35b or connectormeans in the form of connecting pins, as described in a connec tion withFIG. 1 may also be included in the second embodiment. In this case, theconnecting pins (not shown in FIG. 2) may be embedded in the plasticfoil 32 projecting with the outer ends therefrom. In such an arrangementthe foil 32 should preferably be made less flexible to properly hold theconnecting wires in correct position. Contact pins or connecting wiresmay also be used which are held spaced from each other in a rigid plateofinsulating material and connected to the free ends 35b of the wires35, whereafter the connecting portions are surrounded with plasticmaterial. It is also possible to roll the free rear end of the recordinghead 34 substantially to a circle so that the ends 35!; of the wires 35which project beyond the fused plastic layers 32 and 33 form a connectorwhich may be used in conjunction with a connector having suitable matingsurfaces for applying electrical signals to the wires 35.

it will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofrecording apparatus differing from the types described above.

While the invention has been illustrated and described as embodied inrecording heads, it is not intended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended:

l. A recording head for recording on a recording me dium, comprising acarrier; a plurality of one-piece electrically conductive wires embeddedin said carrier in closely spaced parallel relationship, each of saidwires having opposite end portions projecting beyond said carrier andadapted to serve as writing electrodes; and a plurality of electricallyconductive contact pins, each partially embedded in said carrier in adirection substantially perpendicular to said wires and having a firstend connected to said wires intermediate said end portions thereof and asecond end projecting outwardly beyond said carrier, one of said endportions of the respective wire being adapted to conduct electricalsignals to the other of said end portions of the same wire so that saidother end portion serves as a writing electrode and, at the option of auser, said second end of each pin being adapted to conduct electricalsignals to the associated wire so that either or both of said endportions of the wire serve as writing electrodes for interchangeably orsimultaneously writing on the recording medium.

2. A recording head as defined in claim 1, wherein said carrier is a asupporting plate formed of electrically insulating material supportingall of said electrical contact pins.

3. A recording head as defined in claim 1, wherein said carriercomprises two layers of flexible plastic material connected in abuttingrelationship to each other with said plurality of one-piece conductivewires sandwiched therebetween.

4. A recording head as defined in claim I, wherein said embedding meanscomprises substantially rigid insulating material.

5. A recording head as defined in claim I, wherein said contact pins arerespectively connected to adjacent one-piece conductive wires at pointsdisplaced from each other in the direction of said one-piece conductivewires.

6. A recording head as defined in claim 5, wherein the connecting pointsbetween the one-piece conductive wires and the contact pins of theplurality of one piece conductive wires are displaced from each otherthrough equal distances.

1. A recording head for recording on a recording medium, comprising acarrier; a plurality of one-piece electrically conductive wires embeddedin said carrier in closely spaced parallel relationship, each of saidwires having opposite end portions projecting beyond said carrier andadapted to serve as writing electrodes; and a pLurality of electricallyconductive contact pins, each partially embedded in said carrier in adirection substantially perpendicular to said wires and having a firstend connected to said wires intermediate said end portions thereof and asecond end projecting outwardly beyond said carrier, one of said endportions of the respective wire being adapted to conduct electricalsignals to the other of said end portions of the same wire so that saidother end portion serves as a writing electrode and, at the option of auser, said second end of each pin being adapted to conduct electricalsignals to the associated wire so that either or both of said endportions of the wire serve as writing electrodes for interchangeably orsimultaneously writing on the recording medium.
 2. A recording head asdefined in claim 1, wherein said carrier is a a supporting plate formedof electrically insulating material supporting all of said electricalcontact pins.
 3. A recording head as defined in claim 1, wherein saidcarrier comprises two layers of flexible plastic material connected inabutting relationship to each other with said plurality of one-piececonductive wires sandwiched therebetween.
 4. A recording head as definedin claim 1, wherein said embedding means comprises substantially rigidinsulating material.
 5. A recording head as defined in claim 1, whereinsaid contact pins are respectively connected to adjacent one-piececonductive wires at points displaced from each other in the direction ofsaid one-piece conductive wires.
 6. A recording head as defined in claim5, wherein the connecting points between the one-piece conductive wiresand the contact pins of the plurality of one-piece conductive wires aredisplaced from each other through equal distances.